Triangular abrasive for floor finishing machine

ABSTRACT

A drive plate for a concrete or stone grinding/polishing machine includes one or more abrasive elements in the form of short sintered metal bars having diamond crystals mixed therein. Due to the triangular profile of the abrasive elements, as the drive plate is rotated by a drive motor and the apex of the triangular abrasive element engages the floor surface being treated, the abrasive elements are able to more readily strip off mastic, sealers, glue, or most any thin film topical coating present on concrete or other hard floors.

CROSS-REFERENCED TO RELATED APPLICATIONS

None

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None

BACKGROUND OF THE INVENTION I. Field of the Invention

This invention relates generally to motor powered floor finishingmachines and, more particularly, to an improved abrasive for attachmentto a drive plate for such machines, the abrasive being especiallyadapted for removing mastics, sealers, glue, or most any thin miltopical coating such as paint, acrylics, etc. from concrete or terrazzofloor surfaces.

II. Discussion of the Prior Art

The prior art includes many patents and publications describing toolsfor machining stone, terrazzo or concrete floors. Included are machinesfor grinding and polishing, as well as for milling or crushing floorsurfaces. Further, there are machines especially adapted for cleaninghard surfaces, such as concrete, stone and terrazzo by removing coatingson them. Such machines typically carry one or more rotatably mounted,motor driven drive plates that, in turn, carry one or more abrasiveelements attachable to the motor driven drive plate and adapted to berotated in relation to a floor surface. The abrasive elements affixed tothe drive disc typically include abrasive pads or bars that are made toengage the hard floor surface as the drive plate is being driven and themachine is being moved across the floor surfaces. Typical of suchpatents are the Van Vliet U.S. Pat. No. 7,377,838, the Palushaj U.S.Pat. No. 7,690,970 and the Anderson U.S. Pat. No. 7,563,156. A majormanufacturer and supplier of concrete and stone grinding and polishingmachines is Scanmaskin Sverige AB of Lindome, Sweden.

Prior art machines employ a wide variety of abrasive tools bonded,bolted or otherwise affixed to a circular disc where the abrasive toolshave a planar floor-engaging surface. While such tools perform well asfar as grinding and polishing concrete and stone floors, they tend notto be particularly effective in removing paint or glue that had beenused in adhering commercial carpeting or tile to concrete, stone andterrazzo floors.

Once the carpeting or tile is removed, the underlying hard surface floorretains a residue of adhesive material that must be removed prior tofurther refining or finishing the floor.

It is the purpose of the present invention to provide an improvedabrasive element attachable to a drive plate for a floor-finishingmachine that is especially designed to aid in removing paint, mastic,glues, coatings, sealers, or adhesive residues that may be present on ahard surface.

SUMMARY OF THE INVENTION

In accordance with the present invention, a motorized floor finishingmachine comprises one or more circular drive plates having a central hubprojecting out from a first major surface of the circular plate andadapted to be attached to a motor driven drive shaft. Attached to asecond major surface of the drive plate is an abrasive assembly that maycomprise a mounting bracket and an abrasive member affixed to themounting bracket. Alternatively, the abrasive element may be directlyattached to the drive plate. The drive plate may rotate or vibrate orboth.

The abrasive member preferably comprises a sintered metal bar oftriangular cross section comprising a homogeneous mixture of metalpowders, industrial diamond grit and possibly other abrasive materials.

It has been found that when triangular abrasive tools are mounted withtheir base affixed to the drive plate and an opposed apex contacting thefloor surface they are considerably more effective in grinding away thincoatings and adhesives than are conventional abrasive tools exhibiting aflat floor engaging surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features, objects and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription of a preferred embodiment, especially when considered inconjunction with the accompanying drawings in which like numerals in theseveral views refer to corresponding parts.

FIG. 1 is a bottom plan view of a drive plate incorporating fourtriangular abrasive assemblies;

FIG. 2 is a front view thereof; and

FIG. 3 is an exploded view of one of the abrasive assemblies shown inFIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The description of the preferred embodiment is intended to be read inconnection with the accompanying drawings, which are to be consideredpart of the entire written description of this invention. In thedescription, relative terms such as “lower”, “upper”, “horizontal”,“vertical”, “above”, “below”, “up”, “down”, “top”, and “bottom”, as wellas derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”,etc.), should be construed to refer to the orientation as then describedor as shown in the drawings under discussion. These relative terms arefor the convenience of description and do not require that the apparatusbe constructed or operated in a particular orientation. Terms, such as“connected”, “connecting”, “attached”, “attaching”, “join”, and“joining”, are used interchangeably and refer to one structure orsurface being secured to another structure or surface or integrallyfabricated in one piece, unless expressly described otherwise. As usedherein, the term “floor treating machine” is meant to include floorgrinding, floor polishing, floor burnishing, floor scrubbing and swingmachines.

Referring to FIG. 1 and FIG. 2, there is indicated generally by numeral10 one configuration of a drive plate for a concrete, stone or terrazzofloor finishing machine, such as a grinder or polisher. It is seen tocomprise a steel plate 12 having a cylindrical hub 14 affixed to a firstmajor surface 16 thereof where the hub 14 is adapted to receive a driveshaft of a motor for driving the drive plate 12 about a central axis ofthe hub 14.

The second major surface 18 of the drive plate 12 may have a pluralityof symmetrically arranged recesses, as at 20, milled inward from thesurface 18 to form pockets for receiving abrasive assemblies 22 therein.Alternatively, the second major surface of the drive plate may be flatand void of pockets.

Referring to FIG. 3, there is illustrated an exploded view of one of theabrasive assemblies 22. It is seen to comprise the bracket 24 in theform of a metal plate to which is attached one or more an abrasiveelements 26. In the drawings, the mounting bracket 24 is shown as beingsomewhat V-shaped, but with a rounded vertex. However, the bracket shapecan be changed along with the shape of the pockets in the drive plate.As seen in FIG. 3, rather than being a rectangular bar, as in the priorart, the abrasive element 26 is generally a sintered metal bar of apredetermined length dimension and having a triangular cross-section.The abrasive element 26 is preferably attached to the bracket 24 bywelding or silver soldering the base 28 of the triangular abrasiveelement to the bracket.

In use, the apex 27 of the abrasive element opposite its base 28 isparallel to the plane of the drive plate 12. Those skilled in the artwill appreciate that the abrasive elements 26 can also be directlyaffixed to the drive plate 12 without the use of a bracket.

The abrasive element itself is a sintered diamond grit impregnatedmixture of metal powders and possibly other abrasive materials. Withoutlimitation, the triangular abrasive element 26 may have a lengthdimension in a range of from 0.5 inch to 4 inch with an included angleof the apex 27 in the range of 40 degrees to 90 degrees. Withoutlimitation, the size of the diamond grit may be in a range of from 16 to400 on the ASTM scale.

In FIG. 1, the abrasive assemblies 22 are shown mounted in the pockets20 of the drive plate 12 by bolts 34, which pass through apertures 36(FIG. 3) drilled through the brackets 24 and into tapped holes (notshown) formed in the pockets of the drive plate 12. As alreadymentioned, the abrasive elements can be soldered or brazed directly ontothe drive plate 12. The abrasive assemblies 22 may also be attached tothe drive plate by alternative means known in the art.

When removing mastic, sealers, glue, or most any thin film topicalcoating, one of the challenges is surface contact between floor andtool, which generates heat. This heat melts the surface coating, whichgums up and clogs the abrasive tool.

The use of a triangular diamond impregnated segment reduces the contactarea with the floor thereby reducing generated heat. Only a line contactof the apex 27 contacts the floor. Moreover, the active contact is aline formed by the apex 27 in which a row of diamond particles, whichleads to the tool performing a cutting and scraping job as opposed togrinding, the former being more desirable for coating removal. This rowof diamond particles has a much greater number of cutting elements thanthe surface of a conventional rectangular bar segment that has diamondssporadically embedded and is therefore more efficient and effective.

Another advantage of the triangular cross-section diamond impregnatedsegment is the wear pattern that occurs during use. As a prior artrectangular bar segment wears, a full rectangular side surface is incontact with the floor, which not only generates friction and heat, butalso directs the abrasive action downwards. The abrasive element of thepresent invention more laterally interfaces with the floor, presenting ablade-like single row of diamonds to the floor surface as the toolwears.

This invention has been described herein in considerable detail in orderto comply with the patent statutes and to provide those skilled in theart with the information needed to apply the novel principles and toconstruct and use embodiments of the example as required. However, it isto be understood that the invention can be carried out by specificallydifferent devices and that various modifications can be accomplishedwithout departing from the scope of the invention itself.

What is claimed is:
 1. In a motorized floor finishing machine having atleast one circular plate with a central hub projecting out from a firstmajor surface of the circular plate and adapted to be attached to amotor driven drive shaft, the improvement comprising at least oneabrasive member comprising a sintered metal bar of a predeterminedlength and having a triangular cross-section defining a base and an apexopposite said base, where the base is adapted to be joined to a secondmajor surface of the circular plate, said sintered metal bar havingdiamond particles embedded therein
 2. The motorized floor finishingmachine of claim 1 wherein the predetermined length of the sinteredmetal bar is in a range of from 0.5 inch to 4.0 inches.
 3. The motorizedfloor finishing machine of claim 1 wherein the sintered metal bar has anisosceles triangle cross-section and the included angle of the apex isin a range of from 40 degrees to 90 degrees.
 4. The motorized floorfinishing machine of claim 1 wherein the diamond particles have a gritsize in a range of from 16 to
 400. 5. The motorized floor finishingmachine of claim 1 and further including a mounting bracket forinterfacing the abrasive member to the second major surface of thecircular plate.
 6. The motorized floor finishing machine of claim 5wherein the predetermined length of the metal bar is in a range of from0.5 inch to 4.0 inches.
 7. The motorized floor finishing machine ofclaim 5 wherein the metal bar has an isosceles triangle cross-sectionand the included angle of the apex is in a range of from 40 degrees to90 degrees.
 8. The motorized floor finishing machine of claim 5 whereinthe diamond particles have a grit size in a range of from 16 to
 400. 9.The motorized floor finishing machine of claim 5 wherein the base of theabrasive member is affixed to the mounting bracket by one of brazing,welding and soldering.